Not sure if this will work.

[Joe Bifano]

I have 4 rafts getting re-done with new plastic and have 4 - 12" wide x 12" high x 14' long kinda rafts.

What would be the best way to use these.  I have water coming from my auto-siphons entering into the top of one and 2" pipe connecting 2 as a pair. Then I have a pipe coming out the end going back to the fish tank. So it is like a very small raft. But I then added lava rock. I want to grow tomatoes in this and maybe some other things in the winter.

Because I am redoing things I can make a change on these and wanted to know if it will work as I have it or should I change it to be a flood and drain with its' own bell siphon. Give some ideas becasue I want to grow tomatoes and I went with the lava for the heavy roots I will get.

[TCLynx]

Joe, I would say make it a media bed.  If you have good aeration everywhere else and the flow rate is fast enough you probably could have it be constant flood but if you have the capacity to allow it to be flood and drain the tomatoes will probably be happier (though I couldn't tell much difference in growth between my flood and drain beds and the constant flood bed with the tomatoes.)

[Joe Bifano]

So with me keeping the lava rocks and having it constant flood will this work?  Or do I have to change it to have a bell siphon so it drains completely?

[TCLynx]

Just make sure the lava rocks are deep enough that the surface of the gravel stays dry.  Constant flood can work just fine as long as there is enough flow to keep it aerated.